function save(  tbl,filename )
      local file = fs.open(filename, "w")
      file.write(textutils.serialize(tbl))
      file.close()
   end
   
   function load( filename )
      local file = fs.open(filename, "r")
      local tbl = textutils.unserialize(file.readAll())
      file.close()
      return tbl
   end